1. Field of the Invention
The present invention relates generally to machine tools, and more particularly to an automatic tool changer capable of exchanging tools between a tool storage magazine and a tool spindle.
2. Description of the Prior Art
In the past, a plurality of tools have been stored within a tool storage magazine, each of the tools being located at a predetermined angular position thereon, and a tool spindle, having a key member, has been indexed to a predetermined angular position prior to the tool change operation so that a tool inserted within the spindle may be positively driven as a result of the engagement between a key-way of the tool and the key member of the spindle. Therefore, the cut-to-cut time, that is, the time required from the completion of the machining operation by means of the tool held upon the spindle to the start of the machining operation by means of the next tool, has been substantially long.